GeSWall Personal Edition

GeSWall Personal Edition from Gentle Security who are based in Luxembourg
have brought out a nice and FREE application that "dynamically
isolates web browsers, e-mail, chat, P2P, IRC clients and other
applications that may serve as entry points for malicious software
or intrusions. Viruses, trojans, spyware and exploits cannot pass
through an isolated application and so cannot cause any damage."

This application also protects the kernel which in turn stops rootkits
from taking hold.